linux-kernel - detecting integer constant expressions in macros

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 20 Mar 2018 22:13:35 +0000
From:   "Uecker, Martin" <Martin.Uecker@....uni-goettingen.de>
To:     "torvalds@...ux-foundation.org" <torvalds@...ux-foundation.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: detecting integer constant expressions in macros


Hi Linus,

here is an idea:

a test for integer constant expressions which returns an
integer constant expression itself which should be suitable
for passing to __builtin_choose_expr might be:

#define ICE_P(x) (sizeof(int) == sizeof(*(1 ? ((void*)((x) * 0l)) :
(int*)1)))

This also does not evaluate x itself on gcc although this is
not guaranteed by the standard. (And I haven't tried any older
gcc.)

Best,
Martin